Surgical implement detection system

• US 20030066537A1
• Filed: 10/08/2002
• Published: 04/10/2003
• Est. Priority Date: 10/10/2001
• Status: Active Grant

• Current Assignee: Carl E. Fabian, Philip M. Anderson III
• Original Assignee: Carl E. Fabian, Philip M. Anderson III
• Inventors: Anderson,, Philip M. III, Fabian, Carl E.
• Granted Patent: US 7,784,468 B2
• Time in Patent Office: Days
• US Class Current: 128/899
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61F 13/44 with radio-opaque material or signalling means for residual material
• CPC Class Codes: G01V 15/00 Tags attached to, or associated with, an object, in order to enable detection of the object record carriers for use with machines having a detectable tag or marker G06K19/00

Abstract

Surgical implements used during an operating procedure are detected in human tissue. Markers attached to the surgical implements change their impedance at a preselected frequency in the presence of an electromagnetic field. Each of the markers is thereby provided with signal-identifying characteristics. The signal-identifying characteristics are detected outside the operating room in an accurate, reliable manner. Potential interference with operating room electronic instrumentation is avoided, the possibility of operator error is reduced and system cost and space requirements are substantially lowered.

Claims

1. In a system for detecting in human or animal tissue a surgical implement used during an operating procedure carried out in an operating room, wherein a marker attached to said surgical implement changes its impedance at a preselected interrogating frequency in the presence of an electromagnetic interrogating field whereby said marker is provided with a signal-identifying characteristic, the improvement wherein the surgical implement is deployed within the wound during the operating procedure and said signal-identifying characteristic is detected outside the operating room.

2. A system as recited by claim 1, wherein an interrogating means generates said electromagnetic interrogating field, said field having said preselected interrogating frequency modulated as a series of pulses;

said marker resonates at a preselected resonant frequency and radiates a marker dipole field in response to said interrogating field;

said signal-identifying characteristic is a ring-down of said dipole field; and

a detecting means detects said ring-down between said pulses; and

an indication means activated by said detecting means in response to the detection of said marker.

3. A system as recited by claim 1, wherein said marker comprises:

a. at least one magnetomechanical element having a mechanical resonant frequency substantially equal to said preselected interrogating frequency;

b. a bias means for magnetically biasing said magnetomechanical element; and

c. a housing enclosing said magnetomechanical element and said bias means, wherein said magnetomechanical element is free to mechanically vibrate.

4. A system as recited by claim 1, wherein said marker comprises:

a. an electrical circuit having an electrical resonant frequency substantially equal to said preselected interrogating frequency; and

b. a housing for enclosing said electrical circuit.

5. A system as recited by claim 1, wherein said marker further comprises:

a. a piezoeleetric element having a mechanical resonance frequency substantially equal to said preselected interrogating frequency;

b. a coil terminating across the terminals of said piezoelectric element; and

c. a housing for enclosing said piezoeleetric element and coil.

6. A system as recited by claim 2, wherein said interrogating means comprises a frequency-generating means, a field-generating means, and a field-changing means, said frequency-generating means generating said preselected interrogating frequency, said field-generating means receiving said preselected interrogating frequency and generating within an interrogation zone said electromagnetic interrogating field, and said field-changing means varying at least one of the amplitude and direction of said electromagnetic interrogating field to alter the electromagnetic dipole coupling between said marker element and said interrogating field.

7. A system as recited by claim 6, wherein said field-generating means comprises at least one antenna element and said field-changing means comprises means for moving said at least one antenna element to change at least one of the position and orientation thereof.

8. A system as recited by claim 6, wherein said field-generating means comprises a plurality of antenna elements and said field-changing means comprises a switching system that connects a preselected one or more of said antenna elements to said frequency-generating means with a preselected polarity for each element.

9. A system as recited by claim 2, wherein said detecting means comprises a detecting antenna, an antenna-changing means, and a detector circuit connected to said detecting antenna, said detecting antenna receiving said marker dipole field, said antenna-changing means varying at least one of the orientation and position of said detecting antenna relative to said marker element to alter the electromagnetic dipole coupling therebetween, and said detector circuit detecting the presence of said ringdown and activating said indication means in response thereto.

10. A system as recited by claim 7, wherein said detecting antenna comprises at least one selectively activatable receiver element and said antenna-changing means comprises means for moving said at least one receiver element to change at least one of the position and orientation thereof.

11. A system as recited by claim 7, wherein said detecting antenna comprises a plurality of said receiving elements and said antenna-changing means comprises a switching system that connects a preselected one or more of said receiver elements to said detector circuit with a preselected polarity for each element.

13. A method for detecting a surgical implement as recited by claim 10, further comprising the step of:

a. shielding an area surrounding said surgical-implement detector;

14. A method for detecting a surgical implement as recited by claim 10, wherein said marker comprises at least one marker element adapted to undergo resonance at a preselected frequency generated by said surgical-implement detector.

15. A method for detecting a surgical implement as recited by claim 14, wherein said marker element is magnetomechanically resonant.

12. A method for detecting a surgical implement left within a patient after surgery comprising the steps of:

a. attaching a marker to said surgical implement before use during said surgery, said marker having a signal-identifying characteristic in the presence of an electromagnetic interrogating field;

b. placing a surgical-implement detector outside of an operating room, said detector being adapted to generate said electromagnetic interrogating field and detect said signal-identifying characteristic;

c. subjecting said patient after said surgery to said electromagnetic interrogating field generated by said surgical-implement detector;

d. detecting said signal-identifying characteristic; and

e. activating an indication means in response to the detection of said signal-identifying characteristic indicative of the presence of said implement.

16. A method for detecting a surgical implement as recited by claim 12, wherein said detector comprises:

a plurality of antenna elements for generating said electromagnetic interrogating field;

switching means for selectively energizing said antenna elements to change at least one of the orientation and direction of said interrogating field;

a plurality of receiving elements for detecting said signal-identifying characteristic; and

switching means for selectively coupling said receiving elements to said detector to maximize the probability of detecting said marker.

17. A method for detecting a surgical implement as recited by claim 12, wherein said detector is disposed along an exit from said operating room.

18. A method for detecting a surgical implement as recited by claim 17, wherein said detector is disposed along an exit servicing a plurality of operating rooms.